Macdonald P M, Kerr K, Smith J L, Leask A
Department of Biological Sciences, Stanford University, CA 94305.
Development. 1993 Aug;118(4):1233-43. doi: 10.1242/dev.118.4.1233.
Deployment of the bicoid morphogen gradient in early Drosophila embryos requires the prelocalization of bicoid mRNA to the anterior pole of the egg. This anterior localization is mediated by a cis-acting localization signal contained within the 3' untranslated region of the bicoid mRNA. Here we use a series of bicoid transgenes carrying small deletions in the 3' untranslated region to survey for functional elements that constitute the localization signal. We identify and characterize one essential element, BLE1, which specifically directs the early steps of localization. In addition, we find that many deletions within the bicoid mRNA 3' untranslated region impair but do not prevent localization. One such deletion specifically interferes with a later step in localization. Thus the bicoid mRNA localization signal appears to consist of multiple different elements, each responsible for different steps in the localization process.
在早期果蝇胚胎中，双尾形态发生素梯度的形成需要双尾mRNA在前极的预定位。这种前定位是由双尾mRNA 3'非翻译区内的顺式作用定位信号介导的。在这里，我们使用一系列在3'非翻译区携带小缺失的双尾转基因来寻找构成定位信号的功能元件。我们鉴定并表征了一个必需元件BLE1，它特异性地指导定位的早期步骤。此外，我们发现双尾mRNA 3'非翻译区内的许多缺失会损害但不会阻止定位。其中一个这样的缺失特异性地干扰了定位的后期步骤。因此，双尾mRNA定位信号似乎由多个不同的元件组成，每个元件负责定位过程中的不同步骤。
